CARDIOTECH SERVICES, INC.  3027 SHERBROOKE ROAD LOUISVILLE, KY, USA 40205 502 473-7066

ACUTE PHASE PROTEINS

Acute phase proteins (APPs) are a large and varied group of glycoproteins in the serum which are unrelated to immunoglobulin. They are synthesized by liver parenchymal cells and released into the bloodstream in response to a variety of stressors such as local inflammation, bacterial infection, endotoxin injection, neoplasia and thermal or mechanical injury as part of the acute phase of the inflammatory reaction. The synthesis of APPs is thought to be stimulated by monokines such as I1-1, I1-6 and tumor necrosis factor (TNF). Although the response pattern of individual APPs to various stressors or disease may differ, changes in their plasma concentrations are generally regarded as being sensitive, although non-specific, indicators if inflammation.

The biological functions of APPs are also highly variable with some functioning as proteinase inhibitors, enzymes, transport proteins, coagulation proteins, and modulators of the immune response. However, all APPs appear to play a role in the restoration of homeostasis after injury, tissue necrosis, or infection. Some Apps such as C-reactive protein (CRP) and serum amyloid A (SAA) in humans and haptoglobulin in ruminants, are considered "major" Apps and have been used to detect and monitor infection, inflammatory disease, and cancer. Acute phase proteins are also being evaluated for their utility in antemortem and postmortem meat and poultry inspection as part of the Hazard Analysis Critical Control Point (HACCP) program.

The concentration of alpha-acid glycoprotein has been measured in dogs with malignant neoplasia by Olgivie et al (JAVMA 203, No. 8, Oct 15, 1993, 1144-1146). They found measurement of alpha-acid glycoprotein to be useful in monitoring the response to chemotherapy as well as the possibility of recurrence. Continued high levels of this acute phase protein for treatment for conditions where the protein level is high initially suggests that treatment is not working or not appropriate. Levels above 1000 ug/ml of serum indicate a poor prognosis especially if subsequent measurements show increasing levels. We believe the alpha-acid glycoprotein (AGP) information to be potentially useful to practitioners who are advising clients about alternatives to treatment and euthanasia. Elevation of SAA in human transplant patients is associated with pending rejection 100% of the time.

High levels of protein can interfere with normal or optimal vaccine response and the pharmacokinetics of certain antibiotics and other drugs that are known to be bound to proteins in the blood.

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